Pool Rescue after huge storm - Flocculant works.

[acKsw]

Not really a start but a reboot - after 600mm of rain, garden runoff etc, pool was DARK BROWN. Couldn't see the shallowest step, I just turned off the pump and chlorinator and waited for the weather to clear.

First, I put the suction cleaner to work to try and remove some of the debris in the bottom of the pool. I had to empty the skimmer every 10 minutes for most of the day just to clear the debris.

Next morning, a full 15L container of liquid chlorine went in. Was only planning to put half the container in but the phrase "if it's worth doing, it's worth overdoing" came through my mind as I was pouring it. I figured quite a bit of the chlorine would instantly be consumed by the remaining debris. An estimated 45ppm of chlorine instantly turned the brown to milky green.

At the same time I added a double dose of polyaluminium chloride flocculant, with the filter bypassed (recirculate). After an hour or two I saw clumps floating around the pool.

Turned the filter off in the afternoon to let it all settle overnight.

Next morning, a thick fuzzy white layer had settled on the pool bottom and the water was mostly clear. I vacuumed this to waste (the layer was taller than my manual vacuum!) - probably got 90% of it out easily. I figured if I had to do a deep-clean of the filter it wouldn't be the worst thing.

I also re-tested the chlorine. After 24 hours, it had been busy - I now had 0.5ppm left in the pool. Wow. A whole jug, all gone in 1 day.

Following this I put the filter back to normal, with the suction cleaner going to suck the remainder into the filter. Backwashed in the afternoon.

The morning of Day 4 had beautiful crystal-clear blue pool water again. I added a small amount of chlorine to maintain 5ppm, cleaned out the SWG and added enough salt/calcium/bicarbonate/etc to rebalance the water.

Day 1: Mechanical filtration only
Day 2: Massive Chlorine + Floc
Day 3: Vacuum to waste + normal suction cleaner filtering
Day 4: Rebalance water, clean SWG

Since doing this the pool water is the clearest it has been in the past year. I am now unashamedly a Floc convert, I thought I'd have to battle with the pool for weeks to get it right again. TFP likes to preach "you almost never need floc" and while this is true, I think it's far more helpful to say WHEN you DO need it. Floc (and LOTS of chlorine) rescued my pool really fast. Thankyou, floc.

 

[Newdude]

TFP likes to preach "you almost never need floc" and while this is true, I think it's far more helpful to say WHEN you DO need it.

We do. On a case by case basis, with a long disclaimer of how to use it properly to not kill the filter media. Which is almost never. Discussing the rare occurrence on the regular does a huge disservice for all the newbs coming in grasping at straws and hoping for a silver bullet. Just like that flocc they've been sold over and over from the pool store which did zero to fix the root of the problem. (And brought them here).

Even in floods such as yours, and we see several each season, sometimes it helps and sometimes it doesn't.

That all said, I am THRILLED you got yours cleaned up without a lengthy fight. They are awful when they drag out. Well done !!

 

[an1vrsy]

A couple of things I noticed from your post. What's rain? Sorry, I couldn't resist. I live in Las Vegas, southwest U.S. and there has been no appreciable rain here since I moved here at the end of 2019.

The other thing was of course you using flocculant. In most cases, yes, TFP highly discourages the use of floc. It was very important that you went to recirculate, then vacuumed to waste. Good thing taking those steps.

Since it was probably just dirt, couldn't you have just let it settle then vacuumed to waste anyway?

 

[ajw22]

Good job.

Few folks know how to use floc properly. And you have an MPV valve with a recirculate setting. Many folks try and use floc without the proper setup that you have.

 

[acKsw]

Discussing the rare occurrence on the regular does a huge disservice for all the newbs

I'll agree to that, it doesn't need to be regularly thrashed but having the information available (I note the Wiki article has the necessary caveats) is so useful for the times it can help.

That all said, I am THRILLED you got yours cleaned up without a lengthy fight. They are awful when they drag out. Well done !!

Thanks! I was steeling myself for a lengthy fight and everything went better than expected. Mostly due to the information I've gleaned from various places, such as:

It was very important that you went to recirculate, then vacuumed to waste. Good thing taking those steps.

The TFP Wiki and several posts on the matter explained those vital steps.

A couple of things I noticed from your post. What's rain?

Heh. Wait till you get El Nino I guess. Then you'll find out. We're in La Nina and in Australia that's bad for pools. Last year we had 500mm in 7 days, and this year we had 600mm in 14 days. I'm not looking forward to El Nino though, that means dry weather and all the eucalypts here that have been rapidly growing and shedding oily flammable leaves will be quite the fire hazard.

Even in floods such as yours, and we see several each season, sometimes it helps and sometimes it doesn't.

One of the notes on the floc said "if you don't use enough it won't work". So I YOLO'd it and doubled the recommended dose. I've read other comments that using too much acts as a dispersant (??) but this worked brilliantly for me.

Since it was probably just dirt, couldn't you have just let it settle then vacuumed to waste anyway?

Nah it was suspended. The filter was off for 4-5 days and it was hanging in the water column (I could barely see the shallowest step). Given how it went milky green right after the chlorine I'm wondering if it was diatom algae (brown) rather than dirt. With so much rain I had <1000ppm salt left and everything else was at zero, it was basically a freshwater pond.

Few folks know how to use floc properly.

That's most of the reason for my post.

I know it causes a lot of problems, I know it is not recommended 99% of the time, but one of the best things about the internet is sharing KNOWLEDGE. Thanks to picking out fragments here and there I knew enough to know how to use it the right way. So I want to encourage the conversation to be "floc is rarely needed, but here are the circumstances where it is helpful and this is how you need to use it and why you need to use it that way" rather than "floc is rarely needed". When you're on the 20th noob who's asking about floc it's easy to say the latter, but do point them to the wiki page and let them educate themselves like I managed to.

When used in the right circumstances and in the right way, it's bloody brilliant stuff.

 

[CRAD_oz]

Great Post
I went with the other option to clear the dirty water by adding LC, Robot, brushing, Robot and brushing more.